Lithium tetrafluoroborate

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Lithium tetrafluoroborate
Li+.svg Tetrafluoroborat-Ion.svg
Identifiers
CAS number 14283-07-9 YesY
PubChem 4298216
ChemSpider 3504162 YesY
Jmol-3D images Image 1
Properties
Molecular formula LiBF4
Molar mass 93.746 g/mol
Appearance White/grey crystalline solid
Odor odorless
Density 0.852 g/cm3 solid
Melting point 296.5 °C
Boiling point decomp
Solubility in water Very soluble[1]
Hazards
MSDS External MSDS
Main hazards Harmful, causes burns,
hygroscopic.
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions Tetrafluoroborate,
Related compounds Nitrosyl tetrafluoroborate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Lithium tetrafluoroborate is a chemical compound with the formula LiBF4. It can be dissolved in propylene carbonate, dimethoxyethane, and/or gamma-butyrolactone for use as an electrolyte in Lithium-ion batteries.

Applications[edit]

LiBF4 is used as an electrolyte in Lithium-ion batteries. Using LiBF4 instead of the more common LiPF6 salt is advantageous in some applications due to its relative tolerance of temperature extremes[2] and moisture.[3] For example LiBF4 can tolerate a moisture content up to 620 ppm at room temperature whereas LiPF6 readily hydrolyzes into toxic POF3 and HF gases, often destroying the battery's electrode materials. Disadvantages of the electrolyte include a relatively low conductivity and difficulties forming a stable solid electrolyte interface with graphite electrodes.

Because LiBF4 and other alkali-metal salts thermally decompose to evolve boron trifluoride, the salt is commonly used as a convenient source of the chemical at the laboratory scale:[4]

LiBF4LiF + BF3

Production[edit]

LiBF4 is a byproduct in the industrial synthesis of diborane:[4][5]

8 BF3 + 6 LiHB2H6 + 6 LiBF4

LiBF4 can also be synthesized in an inert solvent (e.g. HF or BrF3) from LiF and BF3:[4]

LiF + BF3 → LiBF4

References[edit]

  1. ^ GFS-CHEMICALS
  2. ^ S. Zhang, K. Xu, T. Jow (2003). "Low-temperature performance of Li-ion cells with a LiBF4-based electrolyte". Journal of Solid State Electrochemistry 7 (3): 147–151. doi:10.1007/s10008-002-0300-9. Retrieved 16 February 2014. 
  3. ^ S. S. Zhang;z K. Xu; and T. R. Jow (2002). "Study of LiBF4 as an Electrolyte Salt for a Li-Ion Battery". Journal of The Electrochemical Society 149 (5): A586–A590. doi:10.1149/1.1466857. Retrieved 16 February 2014. 
  4. ^ a b c Robert, Brotherton; Joseph, Weber; Clarence, Guibert; and John, Little (2000). "Boron Compounds". Ullmann's Encyclopedia of Industrial Chemistry: pg. 10. doi:10.1002/14356007.a04_309. 
  5. ^ Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry Vol. 1, 2nd Ed.. Newyork: Academic Press. p. 773. ISBN 978-0121266011.